The invention relates to lamp caps having a cover disc for interconnecting the elongated constricted neck of a halogen lamp to an electrode-bearing lamp holder assembly engageable with such cover disc.
In order to effect a secure connection between certain types of high temperature lamps (e.g., halogen lamps used for automotive applications) and the associated lamp holder assembly which contains electrodes for receiving energizing power for the lamp from the automobile battery or generator system, a lamp cap having a cover disc is conventionally employed. In order to facilitate an efficient electrical and mechanical interconnection between the lamp and the holder through the cap, the neck of the lamp is pinched or constricted to define a substantially rectangular cross-section of reduced area.
Illustratively, the circular interior of the cover disc of the lamp cap is designed to engage the edges of the rectangular neck of the lamp, with a conductive cement being interposed in the interstices between the outer periphery of the neck and the inner periphery of the lamp to assure conductivity. The electrode-bearing lamp holder is then fitted into the assembled lamp and cap.
One disadvantage of lamp cap connections of this type is the necessity of employing expensive conductive cements capable of resisting the extremely high temperatures generated during operation of halogen lamps of this type. Further stresses on the assembly, and particularly on the cemented portion thereof, occur because of the effects of humidity, shock, and other forces common in the operating environments of the lamp. Consequently, it has been found difficult to obtain reliable interconnection between halogen lamps and the associated lamp holders on a mass-production basis.